9. THE CLASS CRUSTACEA
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and from Ireland by Grainger (1951). According to Monod and Dollfus
(1932), the species described by Dollfus (1914) as Trochicola enterica
from the intestine of a marine snail along the coast of France is most
probably identical with M . intestinalis.
Pearse and Wharton (1938) found a single specimen identified as
M . intestindis in an oyster in Apalachicola Bay, Florida, but, as
FIQ. 188. Mytilicolu intestinalis male adult, ventral view. (Redrawn after Steuer, 1902.)
Humes (1954b) has pointed out, it is most probably not M . intestinalis
but M . porrecta.
The known natural hosts of M . intestinalis include Mytilus galloprovincialis, M . edulis, Ostrea edulis, Cardium edule, and the gastropods
Zizyphinus zizyphinus, Gibbula cineraria and G. varia. I n addition,
Hepper ( 1953) has successfully experimentally infected Mytilus edulis,
Ostrea edulis, Crepidula fornicata and Paphia pullastra.
Description. Male (Fig. 188) about 3 mm long ; female about 8 mm
long ; body long and worm-like ; thoracic segments each with a pair of
dorsolateral processes, more conspicuous in females than males ;