1881.] THE SURVEY OF H. M.S. 'alert.' 97 



simply grooved, and not fiinged with spines ; it is situated not far 

 from the centre of the disk. It = 36, r=13; the arms are 7'5 

 millims. wide at the point where they become free from the disk, 

 and 4 millims. at their tip ; the adambulacral spines do not exceed 2 

 milUms. in length ; the interbrachial angles vary very greatly. 

 One specimen taken, at 30 fathoms, iaTrinidad Channel. 



AsTERiNA FiMBRiATA, Pcrrier, Eev. des Stell. 1875, p. 307. 



One small specimen, from Cockle Cove, and two still smaller, from 

 Sandy Point, are, with some hesitation, referred to this species. 

 I have not seen M. Perrier's type ; and the variation exhibited by the 

 species of this genus at various periods of their lives makes it 

 impossible to speak definitely unless one has in hand a considerable 

 series '. 



Astro PECTEN. 



Two dried specimens of a species of this genus were obtained at 

 a depth of 48 fathoms, in lat. 32° 39' S., and long. 50° 11' W. 

 They present a very remarkable resemblance to A. artieulatus. Say, 

 as figured by Agassiz (' North-American Starfishes,' pi. xix.) ; and 

 the two specimens also differ in just the same way from one 

 another as do two specimens mentioned by M. Perrier — in the fact, 

 namely, that in one some of the dorsal plates are provided with spines, 

 while from the other such spines are completely absent. 



The specimens also differ somewhat from one another in the 

 number of dorsal marginal plates. The length of the greater radius 

 of one specimen is 82 milHms., and the number of plates 33 ; while 

 in the other there are 38 plates, with a greater radius of 81 milhms. 

 In the case of both specimens the relation of the greater to the lesser 

 radius is much the same, B being equal to about 5 "75 r, the lesser 

 radius in both specimens measuring 14 millims. 



Two large sword-shaped spines, with which a smaller third one 

 is frequently associated, project upwards and forwards from the upper 

 nirtrgin of the ventro-marginal plate ; they are sufficiently long for 

 the first of each set to extend some way along the side of the dorso- 

 marginal plate next but one in front of it ; extending inwards towards 

 the ambulaeral groove, the plates bear, in a somewhat irregularly 

 double series, as many as seven well-developed spines in each set, 

 and in addition to these there are a number of smaller spines and 

 pedicellarise. From the middle of the arm the spines increase in 

 size towards the angle, and diminish towards the apex. The spines 

 on the adambulacral plates are with difficulty distinguishable : they 

 are arranged in two rows ; and those of the inner series are the 

 longer and stronger ; there are generally three, more rarely only 

 two, on each plate. 



' Since writing the above, another example of the same species has been 

 received from Borja Bay, and I have also been able to see Prof. Perrier's 

 valuable essay on the geographical distribution of the Asterida (Nouv. Arch. 

 du Mus. 1878) ; from this I gather that he seems to be satisfied as to the 

 presence of this species in the Chilian seas (c/. the remarks in the ' B^vision,' 

 p. 308). 



Proc. Zool. Soc— 188], No. VII. 7 



