116 H. J. HANSEN. 
S. serratum (Fabr.), S. rugicauda (Leach), S. Hooker 
(Leach), S. sicilience (Leach), S. trigonum (Risso), S. 
verrucauda (White), S. quadridentatum (Say) (types 
or co-types of the six latter species in the British Museum), 
S. Bolivari (de Buen) (co-types from Canon A. M. Norman), 
S. destructor (Richardson) (co-types from U.S. Nat. Mus.), 
the latter, according to Stebbing, a synonym, as is also S. 
vastator (Bate), to S. terebrans (Bate) ; finally S. mar- 
ginatum (M.-Edw.) (Copenhagen Museum). Of the other 
species described in the literature S. chilense (Dana) and 
S. pentodon (Richardson) seem to belong to this genus. 
Most of the remaining very numerous species established 
in the literature as members of the genus Spheroma belong 
toother genera. Some of them have been or must be referred to 
Exospheroma (Stebb.), viz. S. gigas (Leach), 8. lanceo- 
latum (White), S. leucura (White) (types of these three 
species were seen in the British Museum), S. Stimpsonii 
(Hell.) (Copenhagen Museum), and probably 8. calcareum 
(Dana) ; S. scabriculum (Hell.) is mentioned in the footnote 
on p. 102. S. armatum (M.-Edw.) has been established as 
type for the genus Isocladus (Miers), to which besides 8S. ~ 
spinigerum (Dana) has been referred. S. dicanthum 
(Péron, M.-Edw.) must be aZuzara (Leach); 8. integrum 
(Hell.) is probably a species of Zuzara (Leach), or perhaps 
of Isocladus (Miers). Many species referred to Spheroma 
are in reality females or immature specimens of the genus 
Cymodoce (Leach) ; according to typical specimens in the 
British Museum, 8. spongiosum (White) is the female of 
an Australian Cymodoce, while 8. Prideauxianum 
(Leach), 8. Dumerilii (Leach), S. Griffithsii (Leach), S. 
curtum (Leach), and §S. spinosum (Risso) belong to 
Cymodoce truncata (Leach), and the specimens of 8. 
Ritchianum (Leach) to twospecies of Cymodoce; judging 
from descriptions or figures in the literature, S. Lesueuri 
(Risso), S. granulatum (M.-Edw.), S. pubescens 
(M.-Edw.), S. Gaimardii (M.-Edw.), and S. yucatanum 
(Richardson) have been established on females or young 
