REEOKT ON TIIE ASTEKOIDEA. 25 



The species from the "Blake" dredgings, described by Perrier 1 under the name of 

 Archaster mirabilis, appears to me without any doubt to belong to the genus Pontaster. 

 From the description given, however, I do not feel in a position to assign with accuracy 

 its position in the preceding scheme, and the illustrations render no assistance towards 

 that end. All the figures are stated in the explanation of the plates to be varieties of the 

 form. Several of them, as shown by the phototype, appear very dissimilar in general facies. 

 So far as I am able to judge from the characters mentioned, the form is well distinguished 

 from any of the species herein described. The presence of the papulae at the base of the 

 rays appears to have been observed by Perrier, by whom, however, these organs were 

 supposed dubiously to be genital orifices (loc. cit., pp. 258-260). 



In the subsequently published preliminary note on the starfishes dredged by the 

 "Talisman," M. Perrier 2 has occasion to mention this species, and then refers it, 

 either generically or subgenerically, to CJieiraster (the name being written "Archaster 

 (CJieiraster) mirabilis, E. P."). I am somewhat at a loss to understand this, unless the 

 inaccuracy of Studer's observations as to the remarkable position of the generative organs 

 in the form of a pair of band-like structures along the distal or outer half of the ray — the 

 main character upon which the genus rests — has been proved. For obviously the genera- 

 rative organs could not in one single species hold two such opposite and abnormal positions 

 as that supposed by Perrier in the case of his Archaster mirabilis, and that described by 

 Studer 3 in his Cheiraster gazellse and CJieiraster pedicellaris. 



I have previously referred briefly (ante, pp. 3, 4) to the remarkable characters that 

 are specially regarded by Studer as distinguishing the genera Cheiraster and Luidiaster ; 

 and I would here only draw attention to the striking concordance these forms present in 

 their general facies and the formula of their secondary characters with the genus under 

 notice, if the extraordinary structures upon which their generic claim is based be excepted. 

 I may even mention that in some of the species of Pontaster the position assigned by 

 Studer to the structures which he considers to be generative organs in Cheiraster is occu- 

 pied by a pair of strongly developed muscular bands, which present superficially all the 

 appearances noted by Studer. 



I am under the impression that Archaster coronatus, Perrier, 4 and Archaster echinu- 

 latus, Perrier, 5 will also be found to belong to the genus Pontaster, and perhaps Archaster 

 pulcher, Perrier, 6 may in like manner be included in the same category, though as regards 



1 Bull. Mus. Comp. Zool., 1881, vol. ix. p. 27; Nouv. Archives Mus. Hist. Nat, 2e Sdrie, 1884, t. vi. 

 p. 256, pi. viii. figs. 7, 8 ; pi. is. fig. 4 ; pi. x. figs. 2, 3, and 5. 



2 Comptes rendus, 1885, t. ci. p. 884. 



3 Sitzungsb. naturf. Freunde Berlin, 16. Oct. 1883, pp. 130, 131 ; Anhang z. d. Abhandl. d. L preuss. 

 Akad. d. Wiss. Berlin, vom Jahre 1884, pp. 50, 51, Taf. iv. figs. 8, a, b, e; Taf. v. figs. 9, a, b, c, d, e. 



4 Nouv. Archives Mus. Hist. Nat, 2e Sdrie, 1884, t. vi. p. 262. 



5 Revis. Stell.,?. 348 (Archives de Zool. ezper.,1876, t. v. p. 268); Nouv. Archives Mus. Hist. Nat., 2e Sine, 

 1884, t. vi. p. 263. 



6 Bull. Mus. Comp. Zool, 1881, vol. ix. p. 26 ; Nouv. Archives Mus. Hist. Nat., 2e Serie, 1884, t. vi. 

 p. 254, pL ix. fig. 3. 



(zool. chall. exp. — part li. — 1887.) 4 



