44 Mr. H. J. Carter on 



flesh-spicule is replaced by tlie sceptrella (see my descriptions 

 and illustrations of these two forms of the flesh-spicule in the 

 ' Annals ' of 1879, vol. iii. p. 354 &c., pi. xxix. figs. 11 &c.), 

 and the skeletal spicule is no longer pin-like, but acuate or 

 acerate, as may be seen by the species that have been de- 

 scribed, while in Latrunculia C07'ticata, Carter {ib. p. 298, 

 pi. xxvii. fig. 1 &c.), the form of the flesh-spicule varies from 

 scept7'ellar to spinispirular in the same specimen. So that 

 altogether it appears to me desirable that these sponges should 

 come in immediately after the group Suberitina under the 

 name " Latrunculina." Schmidt has placed them in his 

 " Desmacidinse " (Grundz. Spongf. Atlant. Gebietes, p. 80), 

 because his species, viz. Sceptrella regalis, possesses an ancho- 

 rate flesh-spicule in addition to the sceptrella ; but if the 

 presence of an anchorate or any other form of flesh-spicule be 

 allowed to determine the position of a sponge in classification, 

 the principle, according to my experience, will be found im- 

 practicable. 



On group 13, viz. the Donatina, I have also published 

 observations in the 'Annals 'of 1882 (together with a new 

 species or growth), vol. ix. pp. 356-362, pi. xii. fig. 22, to 

 which I must refer the reader in addition to what is stated in 

 my original classification (p. 182). 



But between Donatina and Latrunculina I would introduce 

 the three other groups mentioned in the same paper and under 

 the same heading, viz. '' Donatina " (p. 356 &c.), «. e. Poly- 

 mastina, Xenospongina, and Placospongina, transferring the 

 " intensely compact " species to which I have therein alluded 

 to a sep>arate group, as I find that, having no mamilliform 

 processes, the latter cannot properly be included in the group 

 Polymastina, however much in other respects, that is in the 

 spiculation, they may resemble each other. Thus, having 

 established a genus of these intensely compact sponges under 

 the name of ^'Trachya " in 1870 ('Annals,' vol. vi. p. 178), 

 and having in 1876 (' Deep-sea Sponges dredged by H.M.S. 

 * Porcupine,' ' vol. xviii. pp. 392 and 393) proposed to place 

 them in the group Polymastina as a subdivision, adding at 

 the same time a brief description of another species equally 

 typical of this kind of sponges under the name of Trachya 

 durissima ('Annals,' 1882, p. 357), I must refer the reader to 

 the last-mentioned as well as to the genus Trachya {I. c.) for 

 the characters of the species which I would here group together 

 under the name of " Trachyina." 



