88 Transactions. — Zoology. 



another Isopod (described in the latter part of the paper) whose nearest 

 allies are marine. Calliope subterranea is inconclusive, for we have in New 

 Zealand one marine and one fresh-water species ; it is, however, not at all 

 near to C. jiuviatilis the fresh-water species, and certainly has not arisen 

 out of that species. 



Gammarus fragilis, again, does not prove anything, for though in New 

 Zealand we have only one species, a marine one, in Europe some species 

 are marine and some fresh-water. The genus Crangonyx contains only two 

 species besides C. comp actus, mihi, one C. subterraneus from a well in Eng- 

 land, the other C. ermanni from warm springs in Kamschatka ; its nearest 

 allied form, however, is a marine genus, Gammarelh. 



On the whole, both the Isopoda and the Amphipoda are so distinctly 

 marine and their fresh-water representatives in New Zealand so few, in 

 fact only two, Calliope fluviatilis and Idotea lacustris, that it is difficult to 

 believe that the subterranean fauna, which, so far as at present known, 

 contains five species, could have arisen from any other than the marine 

 fauna. 



Cruregens fontanus. — Since writing my previous paper I have obtained a 

 great number of specimens of this species — between 40 and 50 — and they 

 all agree in having the last thoracic segment small and without appendages, 

 so that there can no longer be any doubt that the form I have described is 

 the adult form. 



In living specimens the heart can be distinctly seen through the trans- 

 parent integument. It is elongated and extends from the middle of the 

 fifth abdominal segment anteriorly, reaching nearly to the middle of the 

 sixth thoracic segment. The anterior end of the heart is narrower than the 

 posterior part, and the posterior end is rounded. There appear to be three 

 openings through which blood flows into the heart ; one is on the left side 

 in the second abdominal segment ; the other two are on the right side, one 

 in the seventh (last) thoracic segment, and the other in the third abdominal 

 segment. These openings appear to be provided with valves of some kind. 

 Blood passes out through the anterior end of the heart, in the median line 

 of the body, and flows forwards to supply the various parts of the body. 



In my previous paper I have stated that the only blind Isopoda inhabit- 

 ing wells or caves that I could find mention of were two species of a genus, 

 Ca.cidotea, found in the Mammoth Cave of Kentucky and in tbe Wyandotte 

 Cave ; since then I have found two others mentioned, but I have not been 

 able to get descriptions of them ; they are Titanethes albus, Schiodte, which 

 inhabits caves of Carniola* and Tgphloniscus $teinii.\ \ 



* See " Nature," 18th April, 1872, p. 484. 



t See "Trans. Linn. Soc," 2nd ser., vol. I., pt. i., p. 21 (footnote). 

 Others are mentioned in the Zoological Records for 1879 and 1880. 



