34 
or pincer-claws are in the male about three times larger than those of 
the female, and proportionately more robust ; (¢) note also the cells 
for the reception of the inner antennee just below the rostrum, and 
the singular bristle at the apex of the non-retractile eyes. Other 
points already referred to are illustrated on that same card. 
This species is exceedingly abundant in Gerrans Bay, and appears 
to be largely preyed upon by fishes. Mr. Hailstone, quoted by Bell, 
observes that of stated numbers taken at one haul off Hastings the 
proportion of males to females was as two to one. My own obser- 
vations would lead me to say four to one; yet I do not think this is 
any evidence of the proportionate numbers existing in the sea, but 
rather due to the fact that the males may be more inquisitive in 
exploring trammels and crab-pots than the naturally less active 
females. 
The other species, M/acropodia longirostris, does not appear to be 
at all plentiful in this district, though Couch and Spence Bate in 
their “Cornish Fauna” describe it as ‘‘ very common at the depth of 
two to twenty fathoms.” ‘The general aspect of the male /ongirostris 
is very similar to that of the female zostratus, if we ignore the 
prominent abdomen of the latter; it is necessary, therefore, to care- 
fully scrutinise specimens to avoid passing over /ongirostris as females 
of vostratus. ‘The points of specific difference are found in the 
greater length of the rostrum in the former, which exceeds the 
peduncle of the outer antennze ; the possession of a series of minute 
spines on the inner side of the longest joint of the chefe, and two 
small tubercles between the mouth and each outer antenna, instead 
of one as in vostratus. In addition, the body of /ongrostris is more 
elongated and the spines of the carapace sharper. 
Acheus cranchit 1 have not yet found here, and suspect it does 
not occur in Gerrans Bay. Couch and Spence Bate say, ‘Not 
common: deep water among weeds.” ‘The species was discovered 
near here by Mr. Cranch, after whom it is named, and who obtained 
a solitary female specimen whilst dredging off Falmouth. Milne- 
- Edwards says it lives among seaweeds and on oyster beds, and this 
may explain why I have not yet obtained it: the oyster beds are in 
the creeks of Falmouth Harbour. 
lnachus dorsettensis, the most common of the three British 
members of the genus, has not yet come in my way, though Couch 
and Spence Bate record it as common on this coast in crab-pots ; yet 
the less common doryuchus and the rare /eftochirus have fallen into 
my hands, and are now exhibited. The chief differences between 
them may be briefly stated, or at least sufficiently so for the purpose 
of distinguishing them. Just behind the eyes comes the gastric 
region, and in dorse¢fensis this is occupied by a transverse row of four 
small tubercles, and a large one a little behind them (*.*'). In 
dorynchus the same region is adorned by two small tubercles and a 
large one a little behind, the three arranged triangle fashion (-.°). 
In /eptochirus the disposition of the spines and tubercles is very 
