122 Mr. W. S. Kent on a new Genus of Madreporaria. 



poAver of the compound microscope, however, being requisite 

 to define its hirsute character. The ampulla, though sparingly- 

 scattered, are occasionally nearly globular, and of a size almost 

 equalling in diameter that of the ramuscules which support 

 them. 



Mr. Johnson, in describing the species as AlJopora made- 

 rensisy considers it to possess a great general resemblance to 

 StyJaster jiaheUiformis^ and, being under the imjjression that 

 it does not possess ampullffi, is of the opinion that this last 

 circumstance indicates that the two genera Allopora and 

 Stylaster should be united. Admitting the insufficiency of 

 the presence or absence of these episclerenchymatous develop- 

 ments as a generic or even specific diagnostic (which fact 

 I shall amply demonstrate in describing some new species of 

 Allopora proper in a forthcoming catalogue of the Madrepores 

 contained in the British Museum, noAv in course of publication), 

 the alternate-distichal or entirely irregular nature of the gem- 

 mation which obtains in the two respective genera is alone an 

 all-sufficient line of demarcation ; and accordingly, of these 

 two, Mr. Johnson's species is the more closely allied to Sty- 

 laster. 



Mr. Johnson, again, suggests that this species may possibly 

 be identical with the Allopora infundilmlifera of Lamarck. 

 Specimens of the last-named species in the National collection, 

 however, prove it to be very distinct from that interesting 

 form. 



With regard to the true zoological affinities of Stenohelui, 

 the pedunculated and transversely ovate calices all turning 

 the same way, and the subdichotomous mode of gemmation 

 frequently evinced, seem rather to indicate its close relation- 

 ship to (Jryptoltelia of the West- African coast 5 it is, moreover, 

 a remarkable and significant fact that in many instances the 

 lower half of the calyx is as it were thrust in upon the calicinal 

 fossa ; and this may be accepted as a disposition towards the 

 extreme modification in the same region which obtains in that 

 genus, where we find that the inferior half is folded back so as 

 to entirely conceal the calicular fossa. The close proximity of 

 the habitats whence these two genera have been procured also 

 carries with it a highly important significance. 



The genus Endoheh'a of Milne-Edwards may possibly form 

 the immediate intervening link connecting the two genera 

 here compared. It is distinguished by having the inferior 

 edge of the calices developed in a tongue-like form in front of 

 the orifices, though to a less extent than in Cryptolieh'a ; the 

 surface of the coenenchyma is smooth, and both columella 

 and puli are deficient. 



