ECHINODERMATA. 
629 
when we consider (1) the similarity of aspect which these holes always pre- 
sent 5 (2) their size, corresponding to that of the inhabitant ; (3) their in- 
ternal surface, free from attached foreign bodies ; and (4) the circumstance 
that no other boring agent likely to produce such perforations has yet been 
discovered. 
15. How the holes are produced we cannot tell. The dental apparatus 
(Cailliaud), the ambulacral feet (Valenciennes), and the spines (Robert), 
have by different inquirers been presumed to be the agents of perforation. 
On this subject it would be premature to offer any opinion. (Fischer, p. 328.) 
Grube cites seven Sea-urchins from Lossini. He discusses 
at some length the question whether Echinus melo and E, fle- 
mingii be not the same species, which he is disposed to answer in 
the affirmative. Intermediate varieties between these two forms 
certainly occur, and the difference of colour, given in systematic 
works, soon breaks down. A. Agassiz (p. 23), however, makes 
these species distinct. 
Several new genera and species of Echinidea are defined by 
A. Agassiz, who gives, also, the sjmonyms of a number of others, 
previously described. A foot-note refers the reader to the 
Illustrated Catalogue of the Museum,^^ for descriptions of the 
new genera based upon species already known. 
ClDARIDiE. 
Phyllacanthm imperialis (Brandt), found at Zanzibar and Mozambique, is 
distinct from Ph. fustigerus (A. Ag.), from New Holland and the East India 
Isles. The two have been confounded as Cidaris impei'ialis. 
The restricted genus Cidaris should contain only C. thouarsii (Val.), 
C. trihidoides (Lamk. ), C. annulata (Gray), C, haculosa (Lamk.), and their 
allies. C. papillata (Flem.) belongs to Orthocidaris (Ag.), as do likewise 
C. Jiystrix (Lamk.) and C. affinis (Phil.). The species figured as C. haculosa 
by Michelin {not Savigny) is probably identical with Prionocidaris pistillaris 
(A. Ag.). C. tuharia belongs to Stephanoddaris (A. Ag.). 
EchinotTiriic (Pet.) is limited so as to contain only the species having 
broad ambulacra, and spines like those of Diadema. The remaining species, 
with short, longitudinally striated spines, have been removed by A. Agassiz 
to Garelia (Gray). 
Colohocentrotus leshei (Br.) and C. atrata (Br.) belong to different genera; 
the latter to Podophora (Ag.), which includes Echinotnetra quoyi(P\.j 
non P. quoyif Ag.). 
Ildiocidaris chloroticus (Ag.) is referred to Psammechmus, Toreumatica 
reevesii (Gray) to Tethnoplew'us (Ag.), Sahnacis rarispinus (Ag.) to Mehhosis 
(Gir.). 
New genera and species : — 
Gymnoddaris minor, A. Ag. — Sandwich and Kingsmills Islands. C. me- 
tidaria (Lamk.), from Zanzibar, is an allied species. 
Temnoddaris, A, Ag. Known by its apical region deeply notched in the 
