96 
THE VOYAGE OF H.M.S. CHALLENGER. 
6° 36' E., depth, 650 fathoms, 6°‘6 C., clay bottom; lat. 70° 36' N,, loDg, 32° 35' E., 
127 fathoms, 1°’9 C., clay bottom; lat. 72° 57' N., long. 14° 32' E., depth, 447 fathoms, 
0°'8 C., clay bottom; lat. 75° 12' N., long. 3° 2' E., depth, 1200 fathoms, — 1°’6 C., 
biloculina clay; lat. 72° 53' jM., long. 21° 51' E., depth, 223 fathoms, 1°’5 C., clay 
bottom (Hansen). Jan Mayen, 191 to 216 fathoms (Marenzeller). The species, so far 
as known at present, ranges through the Arctic and North Atlantic Oceans, from about 
lat. 75° to 50° N., and from long. 32° E. to 60° W., and from 78 to 1913 fathoms in 
depth. 
Remarks. — The history of this sponge, which is a veritable “ Comedy of Errors,” will 
be found in the report (xxii.) cited above. The claims of Thenea as the rightful 
generic designation, therein advocated, are now generally recognised. Soon after the 
appearance of that report, — this is doubtless what is meant by Vosmaer’s expression 
“about the same time,” — Vosmaer independently adopted the genus Thenea; but while 
I had consented to recognise two species, Thenea wallichii, Wright, and Thenea muncata, 
Bwk., Vosmaer could only accept one, and that the latter. Later writers (Carter, xxiv. ; 
Marenzeller, xxvii.) recognise two species ; Carter after an examination of a large number 
of specimens. The study of the material brought home by the Challenger, and a renewed 
examination of Dr. Norman’s specimens, which include several obtained by Sir Wyville 
Thomson in the “ Porcupine ” expedition, lead me to doubt the correctness of my earlier 
views ; and I am now inclined to admit the identity of Thenea muricata, Bwk., and 
Thenea wallichii, Wright. But which of these two specific names should be retained ? 
Bowerbank admits in the fullest manner the insufiiciency of his MS. descriptions, for 
he states that Gray, in suggesting the genus Thenea, knew nothing of the sponge on 
which it was founded beyond illustrations of a “ single connective spicule ” (Bowerbank, v.). 
As to this I have reason to believe that Bowerbank was in error. AVright’s (vii.) was 
certainly the first clear and complete description of the sponge ; and the identification 
of Thenea muricata with Thenea wallichii would not have been possible but for 
Bowerbank’s subsequent publication in full of the characters of the former (Bower- 
bank, xiii.). This was in my mind when I wrote my paper on Thenea wallichii, Wright, 
and had to choose a name for the sponge of which I was then describing the anatomy. 
It will be seen that material still remains for a very pretty controversy on this 
important question. 
The reference to Stelletta echinoides, 0. Sch. (xvi.), as given by Vosmaer (xxiii.), must 
I think be erroneous ; at all events I am unable to verify it. 
Vosmaer definitely assigns Halyphysema echinoides, Haeckel (xvii.), to Thenea 
muricata, Bwk. That there is a general resemblance between the former and young 
examples of the latter cannot be doubted, it has been noticed and commented on by 
Haeckel himself ; but the similarity extends no further, for the asters of Halyphysema 
