402 PROF. F. JEFFREY BELL ON THE [May 1, 



ACTIXOMETRA PEREGRIXA, sp. IIOV. 



This species belongs to Carpenter's series n. (torn. cit. p. 300), 

 every known species of which, except A. cumiwjii (from Malacca 

 and Queensland) and A. echinoptera (of unknown habitat), belongs 

 to the AVest Indian fauna. .From the two species just named 

 A. peregrina may he at once distinguished by the characters of its 

 cirri, for whereas A. echinoptera ha.-? cirri with eleven joints the nuw 

 species has as many as twenty-five, while there are at least 

 twenty-five cirri arranged in two rows, and not twelve only arranged 

 in one as in A. cumingi. 



The following characters will serve to diagnose the species : — 



Centrodorsal moderately large and a good deal obscuring the 

 radials ; bare in its middle, with about 25 cirrus-pits, the cirri of 

 moderate length with about 25 joints, of which the 5th and 6th seem 

 to be distinctly the longest. The basal joints of the arms very 

 irregular, and no two alike ; the free edge of the joints soon 

 become very finely denticulate. The first syzygy is on the third 

 brachial, the succeeding on the eleventh and eighteenth. Pinnules 

 remarkably well developed even at some distance from the base 

 of the arms. 



Colour brownish. 



Macclesfield Bank, 55-60 £ms. 



Mention also must be made of an Actinometra to which I think it 

 would be wrong to give a specific name, so broken is it, but of which 

 it would be more wrong not to say something. It will be re- 

 membered that the late Dr. H. Carpenter divided the tridistichate 

 species of this genus into those in which there is a syzygy on the 

 second brachial and into those that have it on the third. In the 

 specimen now before me there is no signs of any syzygy on either 

 the second or the third brachial. 



This is another very remarkable fact, and it is most important that 

 we should obtain several specimens of this form, so as to learn 

 whether the absence of syzygies from both second and third 

 brachials is a constant character. If it is, it is certainly one of 

 the most unexpected results, and taken in conjunction with what 

 has been observed in Antedon bassett-etnithi it will severely shake our 

 faith in the value of the site of the syzygy as an aid in specific 

 diagnosis. 



III. ASTEBOIDEA. 



Arciiaster typicus. 



Archaster typicus, M. Tr. Ber. Ak. Berlin, 1840, p. 104. 



In two small specimens dredged, with a large example, in 23- 

 24 fms. of water there are no signs of any spines on the infero- 

 marginal plates ; in a somewhat larger specimen (from 40-46 fms.) 

 there are on some of the plates indications of the growth of spines. 



Archaster tenuis, sp. now (Plate XXY. figs. 4-6.) 



This seems to be a species of Archaster in the sense of 



