Mr. F. Walker oh some new species of Chalcidites. 177 



M^Calla. He observes that in habit and compactness of texture 

 this sponge is a Tethya, and like the species of that genus it is 

 covered by a distinct skin, but the disposition of the spiculse is 

 different, and there is no central nucleus. An additional supply 

 of specimens preserved in spirits has enabled me to verify Dr. 

 Johnston's conjecture, and to prove that this sponge should be 

 removed to the genus Tethya. 



When a longitudinal section of this sponge is made, it is seen 

 to consist of three very distinct substances, an epidermis, a par- 

 enchyme, and a fibrous axis. The epidermis is very thin, of an 

 olive colour, and not perforated by oscula ; the greater part of the 

 sponge consists of a pretty firm orange-coloured substance, per- 

 meated by tortuous canals ; the axis is white, of a fibrous texture, 

 and easily distinguished from the parenchyme by its colour and 

 structure. From the presence of this fibrous axis, we think this 

 sponge should be removed from the genus Halichondria to that 

 of Tethya, 



This species was originally found at Roundstone by Mr, 

 M'Calla, and it appears to be a common species, for the same 

 indefatigable observer has lately obtained specimens from Belfast 

 Lough, where, as at Roundstone, it is associated with the Hali- 

 chondria cegagropila. 



XKVII. — Characters of some undescribed species of Chalcidites. 

 By Francis Walker, Esq., F.L.S. 



[Continued from p. 115.] 



13. Encyrtus Cervius, mas. Cyaneo-viridis, abdomine nigra, an- 

 tennis pedibusque piceis, alls limpidis. (Corp. long. lin. ^; alar, 

 lin. 1.) 



Body rather narrow, slightly pubescent : head and thorax bluish 

 green, convex, squameous : head transverse, short, rather broader 

 than the thorax ; vertex broad ; front abruptly declining, slightly im- 

 pressed : eyes of moderate size, not prominent : ocelli disposed in a 

 triangle on the vertex : antennae piceous, subclavate, slender, inserted 

 near the mouth, rather longer than the thorax; first joint long, 

 slender ; second long-cyathiform ; the following joints from the third 

 to the eighth successively though slightly increasing in breadth ; club'' 

 fusiform, more than twice the length of the eighth joint : thorax oval : 

 prothorax transverse, short, narrow in front : scutum of the meso- 

 thorax broad ; parapsides united to the scutum ; axillae complete ; 

 scutellum obconic : propodeon subquadrate, declining, of moderate 

 size : podeon extremely short : abdomen elliptical, depressed, black, 

 smooth, shining, much shorter and narrower than the thorax ; me- 

 tapodeon, octoon and ennaton of moderate size ; the following seg- 

 ments very short : legs pioeous ; mesotibi?e and mesotarsi dilated, and 



Ann. ^ Mag. N. Hist. Vol. xvii. O 



