Mr. F. Walker on 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 spicule 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 egagropila. 
XXVII.—Characters of some undescribed species of Chalcidites. 
By Francis Waker, Esq., F.L.S. 
[Continued from p. 115.] 
18. Encyrtus Cervius, mas. Cyaneo-viridis, abdomine nigro, an- 
tennis pedibusque piceis, alis 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 : antennz 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; axille 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 piceous ; mesotibie and mesotarsi dilated, and 
Ann. & Mag. N. Hist. Vol. xvii. O 
