Report on the zoological collections made in the Indo-Pacific Ocean ...

—;436 COLLECTIONS FROM MELANESIA.15 millim, in greatest and least thicknesses respeetiTOly, spreadingover and uniting three detached stones, from which arise two chiefand a few incipient lobes, the largest respectively 12 and 25 millim.in height. The species differs from the Torres-Straits and Malaccaspecies (/. jmrpurea) in the presence of the cylindrical dermalspicule, in the stouter stem, and the much more finely roughenedsurface; it is more nearly allied to D. {Ilaruhomlria) hirotnlifera,Higgin (from the West Indies), which it resembles in stoutnessof habit ; but the cylindrical and acuate spicules are both twice thediameter of the corresponding spicules of that form.69. Esperia parishi.Rapliiodesma parisbii, Boiverhank, P. Z. S. 1875, p. 283.Amphilectus parisbii, Vosmaer, Notes Roy. Mus. Netherl. ii. p. 119.An indubitable Esperia. Dr. Bowerbank's description of thespicnlation of this species is defective and misleading ;he omits tonotice the sheaves of " trichites''which I find in his preparationsthey are, as usual, local in their occurrence, and, from their delicateproportions, not easy to find ; the slender bihamates describedmay be traced by intermediate stages up to the large bihamates,which are perhaps the most striking feature of the spiculationthey are thus merely the young of these latter forms : the allegedspincd acuates and tricurvates obviously belong to a Myxilla overwhich the Esperia has grown, as they occur in abundance together,but not all over the " basal membrane." (Some navicular equianchorateswhich occur seem to be also foreign, being found onlydetached and in small numbers, and but local in their distribution.)I am inclined to consider the small " palraato-inequianchorates " asyoung forms of the normal large one.The following are the proportions of the different spicules properto the sponge ; they agree fairly in both the Malacca and Australianspecimens :1. Smooth, subspinulate acuate, with slight elongate head; basalend slenderer than middle of shaft : ''i'd by '013 millim.2. Large inequiauchorate ; large end comparatively short, itstubercle long and narrow^ : -057 millim. long.3. Navicular equianchorate: -013 millim. long.4. Bihamate, smooth, contort : -095 by -008 millim.5. Trichite spicules in bunches of two to four or five :-032 to -16by -0018 millim.Some thin fragments agreeing well in all respects with the typicalpecimen occur in the present collection.Hah. Port Darwin, between tide-marks.Distrihntion. Straits of Malacca {BorverhavTc).This si)ecies appears to be absent from Torres Straits, judgingfrom the results of the numerous dredgings taken there ; its presenceat Port Darwin is therefore probably to be accounted for by directtransit across the western end of the Arafura Sea by way of Timorand the neighbouring islands.