Mr. H. J. Carter on the Siibsphercnis Sponges. 23 



described in new terms, for the most part borrowed from the 

 Greek, instead of from the language of the country, which 

 would supply nearly all that is necessary, must ever prove 

 more or less enigmatical, and therefore correspondingly tire- 

 some and impracticable. 



We shall never get a satisfactory idea of the Spongiadge 

 until the species have been simply but truthfully figured side 

 by side with their elementary parts, and as simply described. 

 Association, with both, will then supply what the latter certainly 

 fails to do separately. 



It was with this view that I sent home to Dr. Bowerbank 

 nearly all the collection I made on the south-east coast of 

 Arabia, tliinking that he was about to accomplish this great 

 work, which requires a master mind of no ordinary ability to 

 produce, and the confidence of a bold publisher to print. But 

 my collection, with many others, are locked up in Dr. Bower- 

 bank's El Dorado, which, like his papers published successively 

 by the Koyal and Ray Societies, contain many good things, if 

 one could only get at them. 



Classification. 



A glance at my figures will show that Tethya Jyncuriuni 

 differs so much from T. arabica that it cannot rightly be 

 placed in the same genus with the latter ; while T. arabica 

 is so nearly allied to T. cranium that these two also must of 

 necessity come together. Hence Dr. J. E. Gray, in his ar- 

 rangement (Proc. ZqoI. Soc. Lond. May 9, 1867), has very 

 properly made a separate genus, under the name " Donatia^'' 

 for T. lyncurium. His third or " club-shaped " spicule is but 

 a modification of the subulate or awl-shaped form common to 

 the species. 



Again, for sponges of the type of Tethya cranium he has 

 assigned the term " Tethya;" and here my T. arabica must of 

 course come. Thus Donatia and Tethya form the first genera 

 respectively of his first and second divisions of the Tethyadae. 

 Dr. Bowerbank places both under the genus Tethya. 



Under Dr. Gray's Tethya should also come my T. dacty- 

 loidea^ described and figured in the ' Annals ' for January last 

 (p. 15), which, I regret to state, lacks minute detail, from my 

 having parted with the specimen. 



The genus Pachymatisma naturally appears first in Dr.Gray's 

 family of Geodiadge ; and my G. arabica^ being closely allied 

 to G. zetlandica^ under his third genus, viz. that termed 

 " Cydonium." 



With Dr. Gray's love for the subject, together with his great 



