86 CATALOGUE OF THE BLASTOIDEA. 



ovarian tubes beneath it. Nevertheless, Hambach describes a " cone-shaped body " 

 on the summit of well-preserved specimens of Pentremites sulcatus 1 , which " consists 

 of little tubes running parallel with each other, and roofing in the summit of the 

 calyx in a conical shape (but not the central opening). They protrude through the 

 same apertures in which the hydrospires terminate ; there are about five of these 

 tubes to each aperture, which seem to correspond with the plicas of the hydrospiric 

 sac, and if they extend down into the interior of the calyx, as I suppose they do, then 

 the only space which could have been occupied by them is below the hydrospiric sac 

 and between the plicas, because they are isolated tubes and consequently not a con- 

 tinuation of the hydrospires. This would explain the necessity of the solid support 

 of the plicas, which was undoubtedly to prevent an obstruction in the passage of 

 these tubes, which I take to be the ovarian tubes." 



Not having seen the original of Hambach's description, we can naturally say but 

 little about it. Nevertheless we much doubt whether this cone-shaped body is any- 

 thing more than an aggregation of the proximal pinnules 2 as represented in PI. V. 

 fig. 28 ; and in any case we are at a loss to understand how ovarian tubes which 

 occupy the position described by Hambach could open to the exterior through the 

 spiracles. We see no reason for calling these openings " ovo-spiracles " as Hambach 

 does. The name is not only rendered more cumbersome by the addition of two 

 syllables, but it also becomes absolutely incorrect. For there is no reason to think 

 either that the Blastoids were hermaphrodite, or that they were all females ; 

 while there must still be a certain amount of doubt as to whether the genital glands 

 of the Blastoids may not have been situated in the pinnules and have liberated their 

 products directly, just as in the Crinoids. 



Hambach has further committed himself to the remarkable doctrine that the outer 

 side plates (supplemental pore-plates of Roemer) of a Pentremite are the remains of 

 collapsed tentacles which were in communication with the hydrospire-sacs and pro- 

 truded through the pores at the sides of the ambulacra. He is careful to explain 3 

 that by " tentacles " he does not mean the pinnules, to which organs this name has 

 often been erroneously applied by other authors ; but he uses it to denote the softer 

 and membranous ones, " such as occupy the pores of the ambulacral field in Echino- 

 derms." It is difficult to understand what can have induced Hambach to revive 

 Say's theory 4 that " the branchial apparatus communicated with the surrounding 

 fluid through the pores of the ambulacra? by means of filamentous processes." For in 

 the sixty years since Say wrote it had been discovered that the tentacles of an Urchin 



1 Trans. St. Louis Acad. Sci. 1884, vol. iv. uo. 3, p. 54:.'. 



2 See Chapter IV. p. 70. 



3 Trans. St. Louis Acad. Sci. 1880, vol. iv. no. I, p. 151. 



4 Joum. Acud. Nat. Sci. l'hilad. 1825, vol. iv. pt. 2, p. 296. 



