Mr. H. J. Carter on Stromatopora. 85 



pede ; and in this I am inclined to believe. Dr. Power in his 

 drawing has figured the pupa of Carcinocystus so that it ap- 

 pears to have a long proboscidiform mouth that is capable of 

 being extended beyond the margin of the walls of the cara- 

 pace, and so, we may presume, enabling it to feed ; and 

 it is difficult to imagine that an animal can grow to so 

 large a size as this is in its adult condition if it had not the 

 existence of an animal, both in feeding and selection, after it 

 had passed beyond the NaupUus-cowdiiixon, 



Metschnikoff appears to me altogether to beg the ques- 

 tion when he asserts that Nauplius is the larval form of 

 Pencsus^ because it resembles that of Euphausia in certain 

 conditions of development. After fully considering the sub- 

 ject, it appears to me that Fritz Miiller's Nauplius may be 

 the larval condition of a Schizopod, more or less related to 

 Euphausia, or it may be the young of one of the Suctorian 

 parasites, but that there is every reason to believe that it is 

 not the young of any known prawn, and there is no evidence 

 to determine its relation to Penceiis. 



X. — On Stromatopora. 

 By H. J. Carter, F.R.S. &c. 



In my last paper (' Annals,' 1878, vol. i. p. 412) it is stated 

 that the " hexactinellid structure," therein mentioned, "if 

 not a sponge was still not a Stromatopora ;" and further on, 

 *' at least " not of " the type to which I allude." 



I am now able to solve the difficulty by having a short time 

 since, through specimens of Babbicombe (Devonian) Lime- 

 stone brought to this place (Budleigh-Salterton) for calcina- 

 tion, found that the " hexactinellid structure " is presented 

 by Stromatopora concentrica, and just now, by the kind aid 

 of Mr. Vicary, together with his books and specimens, have 

 also been able to determine that the latter is Gaimopora, Phill., 

 \'^Ai\,=^ Stromatopora placenta, Lonsdale ap. Baily (see most 

 satisfactory representations of both species in Phillips's ' Pala30- 

 zoic Fossils of Cornwall, Devon, and West Somerset,' 1841, 

 pi. X. figs. 21, 29). 



These two points have been verified by an inspection of Mr. 

 Vicary's great collection of Stromatoporcp. to which I have 

 before alluded, whereby it seems to me that, to expose the 

 hexactinellid figure, the plane of section must be tangential 

 to the curve of undulation in the layers of the Stromatopora, 

 or horizontal to its summit — also that the more abrupt the un- 



