ECHINOIDEA. II. 



159 



vvheii I venture to suppose that Br. lyrifcra is not at all found on the American side of the Atlantic. 

 In any case it cannot be taken as proved by any of the statements hitherto made of its occur- 

 rence there. 



From the U. S. National Museum 1 have received a specimen of «.Brissopsis lyrifcra-^ from 

 «Albatross> St. 2401 (142 fathoms; Gulf of Mexico. Rathbun 336. p. 616), which is evidently identical 

 with the «globular type figured by Agassi z in Blake -Ech. PL XXVI. Figs. 13—18. Specimens of 

 the same form I have further seen in the U. S. National Museum, the Museum of Yale College and 

 in the British Museum from the < Albatross St. 2400 and 2401 and from the s Blake = St. 49. From the 

 latter station there are three specimens of this form in the British Museum wrongly identified as 

 Periastir liiiucola A. Ag. — A close examination of this form shows that it is not Br. lyrifcra., but a 

 very distinct species, which I shall describe here under the name of Brissopsis alta n. sp. 



The shape of the test (PL III. Figs. 5, 8, 9, 13, 16) is distinctly higher and more globular' than 

 in lyrifcra, as is also well seen in the figures in the .Blake»-Echinoidea quoted above. The actino- 

 stome is very near the anterior end jof the test, distinctly more so than in lyrifcra. The labrum is 

 prominent, with a rather broad posterior prolongation, not reaching the second adjoining ambulacral 

 piates. The first ambulacral plate reaching within the subanal fasciole is the 6th; three pairs of pores 

 are enclosed within the fasciole. No anal branches of the fasciole are developed. The rather small 

 anal area is placed near the upper side on the high, beautifully arched posterior end. The petals are 

 short and rather broad, the posterior about two thirds as long as the anterior ones; in larger speci- 

 mens they are rather deepened. The posterior petals are completely separated, though scarcely so 

 widely as is generalh- the case in lyrifcra; the tubercles appear already on the second — third plate of 

 the posterior interambulacnun (as in lyrfcra), and only the three iniier pores of the inner series of the 

 posterior petals are rudimentary. The area enclosed by the peripetalous fasciole is somewhat smaller 

 than in lyrifcra; it is rather broad, not much narrowed in the posterior lateral interambulacra, produced 

 somewhat backwards in the odd posterior interambulacrum. The odd anterior ambulacrum is only 

 slightly sunken, the front end of the test being almost regularly rounded, especially in the smaller 

 specimens. In the specimen received from the U. S. National Museum there are only three genital 

 pores, which is, however, evidently an abnormal case, all other specimens seen by me having four 

 genital pores. — The tubefeet and their spicules are as in lyrifcra, the spicules only may be a little 

 more thorny. vSome of the rosette-plates may be coalesced. 



The pedicellariæ give very good characters distinguishing this species from lyrifcra. The glo- 

 biferous pedicellariæ (PL XVIII. Fig.s. 27, 29) have the terminal opening of the valves surrounded by 

 6 or 8 short teeth; the blade is a quite closed tube, somewhat curved. The basal part has a rather 

 close meshwork at the bottom; the edges are smooth as is also the apophysis. The valves are as in lyri- 

 fcra enclosed by a thick skin, probably glandular, but without glandular sack. There is no neck. The 

 stalk is provided with an irregular, sometiraes very large limb with numerous free, upwards directed 



I lu the Blake. -Echinoidea (p. 70] Agassiz sets forth the opinion that the «globular test« is an «embr>'onic feature«. 

 I cannot see the reason for regarding this shape of the test as more embryonic than the oval, elongate form. If it be proved 

 that a species like the Br. elongaia described below is globular in its young stages, there may be some reason for seeiiig a 

 more primitive' feature therein. But, as far as my experience goes, it cannot be said to be a general character of young 

 Spatangoids that their test is comparatively more globular than the test of the grown specimens. 



