DESCRIPTIONS OF THE SPECIB8. 263 



lanceolate (PI. XII. fig. 1); sharp in C. Wkitei, and barely separating the slits of 

 adjacent interradii at their outer extremities. They become wider, however, towards 

 the mouth, and their proximal ends in this species, and inC. alternatus, var. elongatus, 

 bear small tubercles (PL X. fig. 19). In the latter form the oral ridges project 

 somewhat above the general summit and slope inwards (PL X. fig. 20) ; but in 

 C. pyramidatus they are inclined outwards, and to a certain extent also in C. Hindei 

 (PI. XII. figs. 2, 5). In the British C.trilobatus they are to all intents and purpo ea 

 flat (PL XIII. figs. 1, 4). The radial sinuses are short in all the species. The anus 

 is either more or less rhombic, as in C. pyramidatus (PL XII. fig. 1) and C. trilobatus 

 (PI. XIII. figs. 1, 4), or ovate, as in C. alt (run his, var. elongatus (PL X. fig. l'J). 

 Codaster is closely allied to Phamoschisma in the exposure of the hydrospire-slits on 

 the surface of the calyx, and in the absence of definite spiracles; but in the latter 

 genus the anal interradius is occupied by hydrospires (PL XIV. figs. 5, 11), and the 

 outline of the calyx in the two genera is often quite different. 



Codaster has no connection whatever with Stephanocrinus, the peculiar characters 

 of the latter type placing it quite apart from this and from other genera, especially 

 as it is now known not to be a Blastoid at all ; and we most emphatically protest 

 against the statement of Prof. James Hall that " there are no differences which appear 

 to be of generic importance between Stephanocrinus and Codaster" l . Such a belief 

 could only have arisen from a total misapprehension of the structure of the latter 

 genus. 



Amongst the synonyms of Codaster, Dr. Bronn 2 in 1S60 placed " Astrocrinites, 

 (.'umb. (non Austin)," but after much patient research we are quite unable to decide 

 to what genus of Cumberland's Dr. Bronn referred. Cumberland certainly never 

 described an "Astrocrinites." The genus Heteroschisma has been recently proposed 3 

 by Mr. C. Wachsmuth for the reception of three species which appear to him to 

 differ from Codaster in the relation of the hydrospires to the deltoid plates. The 

 species in question are said to have relatively small deltoids like Phamoschisma, while 

 resembling Codaster in the absence of hydrospires from the anal interradius. The 

 differences between the deltoids of Codaster and those of Heteroschisma, as described 

 by Wachsmnth, are so great that were we convinced of their existence, we should 

 be compelled to place Heteroschisma in a separate family by itself 4 . We find, 

 however, not only that the deltoids of C. pyramidatus, Shum., and C. Hindei, nobis, 

 are essentially similar to those of the type C. trilobatus, McCoy (PL XII. figs. 1-C ; 

 PL XIII. figs. 1, 4, 8), but that the same is true of the variety of Codaster (Hetero* 

 schisma) alternatus, Lyon, which is termed elongatus by Mr. Wachsmuth (PL X. 

 figs. 19, 20), and also of Mr. Wachsmuth's type Heteroschisma gracile (PL XVI. 



1 Colktt's 1 lth Ann. Report, Dept. Geol. & Xat. Hist. Indiana for 1881 [1S82], p. 280. 



2 Klassen und Ordn. Thier-Reichs, 18G0, Bd. ii. p. 189. 



3 Report Geol. Survey Illinois, 1883, vol. vii. p. 352. * See autoi, pp. 30-34. 



