246 BULLETIN OF THE 



& Trosch.,* but without recognizing any specimens, and in his description 

 seems to have included tins and O. echinata under the name of O. fragilis. 

 In the collections of Professors Grube and Richiardi, and at the museum of 

 the Palazzo Ducale in Venice, I found nearly a dozen specimens, collected 

 chiefly near Trieste ; and there are others in the museums at Copenhagen 

 and at Stockholm. They present pretty uniform characters,, and attract 

 attention by the close-set crop of long, glassy, or silvery spines, by which the 

 disk is almost hidden ; closer examination shows that there are no stumps at 

 all on the disk, and that the radial shields are either absolutely naked, or 

 have only a few extremely minute spines. Moreover, the animal is distin- 

 guished usually by its dark green color, with which the spines contrast, like 

 spun glass. A specimen with a disk 12 mm. in diameter, and arms 96 mm. 

 long, was dark green, with lighter mottlings on the radial shields, which 

 were naked. The upper arm-plates were rhoinboidal, overlapping, and with 

 a well-marked lobe without. The arm-spines were nine, flat and regular ; 

 longer, more tapering, and more glassy than in O. echinata, and with sixteen 

 or seventeen thorns on an edge. The longest one (usually the second) was 

 to the upper arm-plate as 3.2 : 1. The disk-spines were uniform in shape, 

 being stout at the base, tapering, somewhat flattened, forked at the tip, and 

 with a few very minute thorns on their sides ; their length on the back of the 

 disk was 1.2 mm., near the edge longer. Other specimens did not vary 

 essentially from this, except in the comparative length and slenderness of the. 

 disk and arm-spines; the former having sometimes a regular fluted form 

 (PL III., Fi". 1) and a maximum length of 3 mm. The radial shields are 

 usually wholly naked, but may have a few minute spines, not over .2 mm. 

 long (PI. III., Fi<*s. 2, 3). One specimen had a light-colored disk, with a 

 black spot on each radial shield, and dark upper arm-plates. 



There seems no question as to the distinction of the four species just 

 noticed ; there are now to be considered some whose claims are less clear. 

 The Asterias pentaphyllum of Pennant is an inhabitant of the English coast; 

 Lutken considers it a variety of 0. fragilis, while Ljungman regards it as a 

 good species. Those I have seen were from the Isle of Wight and from Ma- 

 deira (?) ; they were readily distinguished from 0. fragilis, but, as there were 

 no young forms, I am unable to speak with a full knowledge. The disk is 

 flat and round, and not puffed; radial shields naked and conspicuous; upper 

 arm-plates with a well-developed peak on the outer side. The disk-stumps 

 and spines seem in their young state to be thorny grains (PI. II., Fig. 30) and 

 not forked stumps, as is usual; from this form develop larger grains and 

 thick stumps (Figs. 31-33) and even columnar spines (Figs. 34, 35); the 

 more pointed spine (Fig. 3G) was found only on two specimens, said to come 



* The original examined by Trosche] no longer exists atLeydcn, but the present 

 ideatification of 0. alopecurus seems a reliable one. 



