REPORT ON THE TETRACTINELLIDA. 
CXXXl 
Genus 4. Sphinctrella, 0. Schmidt. 
SpMnctrella, O. Schmidt, Spong. Atlant. Gebiet,, p. 65, 1870. 
Vulcanella, Sollas, Sci. Proc. Roy. Dubl. Soe., N.S., vol. v. p. 186, 1886. 
Theneidse of no regular form, distinguished by one or more large oscules, which are 
fringed at the margin by long oxeas, and lead into cloacas with fenestrated walls. Special 
poriferous recesses are absent. The spicules and skeleton are similar to those of 
Pcecillastra. 
Type — Sphinctrella horrida, 0. Schmidt. 
The Sponge on which I founded the genus Vulcanella is so different in general form 
and outward appearance from Sphinctrella horrida^ and Schmidt’s descriptions are so 
incomplete, that it was not till I had an opportunity of examining a fragment of Schmidt’s 
species that I noticed the resemblance ; since then I have found in the Challenger 
collection two other species, which are more like Sphinctrella horrida in general character, 
and there can be little doubt as to the identity of Vulcanella with Sphinctrella. 
Genus 5. Triptolemus, n. gen. 
Theneidse of no regular form, usually incrusting. Oscules and pores not known. 
The megascleres include an oxea and centrotrisene, the microscleres a spiraster and spinose 
microxea. 
Type — Triptolemus dadosus, n. sp. (p. 93). 
The first discovered species of this genus were assigned by Carter,^ who described 
them, first to Pachastrella, and subsequently to Samus ; beyond the characters and 
arrangement of the spicules, but little is known about them, and so long as the characters 
of the chamber-system are uncertain, the position of the genus is more or less open to 
question. 
Genus 6. Stceha, n. gen. (provisional). 
Theneidse of no regular form ; in the only species known burrowing. The mega- 
scleres are dichotrisenes, the microscleres spinose microxeas. 
Type — Stoeha simplex (Carter) (p. 102). 
This is another of the Sponges assigned by Carter to the genus Samus ; in that genus 
as redefined by us it cannot be included, and since there is no other existing genus to 
which it can be referred, it becomes necessary to institute a new one to receive it. 
‘ Carter, Ann. and Mag. Nat. Hist., ser. 4, vol. xviii. p. 410, 1876 ; Carter, op. cU., ser. 5, vol. vi. p. 60, 1880. 
