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

——PISCES, 31are :Two specimens were collected at Port MoUe. Their dimensionsTotal length27 lines.Length of tail Hi ,,Length of head 5 „Length of snout ^| „BRANCHIOSTOMA.The recent discovery of a second undoubtedly distinct species ofLeptocardian on the coast of Australia {Epigoniclithijs cultellus)as well as the acquisition of several well-preserved examples, forwhich we are indebted to Dr. Coppinger, induced me to reexamineall the specimens in the British Museum, which, having been preservedin spirit for a great many years, Avere by themselves notreliable evidence as to the question whether the European Lancelotis a cosmopolitan form, or represented by several distinct species inother parts of the globe.J. Miiller (' Ueber d. Ban d. BrancJiiostoma,' p. 84) was unable toobserve any differences between Brazilian and European specimens ;and I not only took the same view, but considered specimens fromIndian and Australian localities to be referable to one species only.I have now convinced myself that this view (Cat. Pish. viii.p. 513) is incorrect, and that Sundevall was quite right in drawingattention to the number of myocommas as an excellent taxonomiccharacter. This number can be ascertained even in specimens inan indifferent state of preservation, and varies very little ; whilstthe extent in depth and length of the delicate fin which surroundsthe posterior part of the tail is a much less reliable character, subjectto much alteration by the spirit, if great care is not taken in thepreservation of the specimens.The species of Bramhiostoma would then be the following :1. Brancliiostoma elongatum.Sundevall, (Efvers. Vet.-Akad. Forhandl. 1852, p. 147; and 1853,p. 12.Myocommas 49 + 18 + 12=79.Coast of Peru.Of this species I have not seen specimens.2. Branchiostoma bassanum.Myocommas 44 + 13 + 18 = 75, or43 + 15 + 17=75, or45 + 14+17=76.Body lower than in B. lanceolatum ; dorsal and anal fins low,with the caudal portion slightly wider ; vent lateral ;(oral cirrhi10 + 11).These are the specimens from Bass-tStraits which I formerlyreferred to B. lanceolatum.