PROCEEDINGS OF SCIENTIFIC SOCIETIES. 185 
growing in living Bryzoa and Sponges,” by Dr. P. H. Renisch. The latter, 
however, dealt with the subject more from a botanical than zoological point 
of view. Mr. Waters remarked that Dr. Renisch rather referred to examples 
of Hydroida than true Polyzoa. Prof. Duncan, in a brief reswmé of the 
points at issue and of what was known generally on the subject of the 
parasitism in question, referred to a number of corals so affected, and-stated 
that many of the fossil forms bore evidence of filaments penetrating their 
calcareous structures. 
The Secretary read, in the absence of the author, a paper “On the 
Classification of the Maioid Crustacea, or Oxyrhyncha,” by Mr. Edward J. 
Miers. The Maioid Crabs have been placed by nearly all carcinologists at 
the head of the Brachyura, from the high degree evinced in their sensory 
organs and nervous system, and the group, moreover, is interesting on 
account of the variety of their types. Exteriorly they are distinguished by 
their more or less elongated carapace, an anteriorly narrow large epistoma, 
longitudinal antennules and situation of basal antennule joint. Their buccal 
cavity is quadrate; the branchie are nine on each side, the afferent canal 
opening in front of the anterior legs, and the efferent at the sides of the 
buccal cavity ; while the male genital appendages arise from the bases of the 
fifth pair of ambulatory legs. Though closely related to the Oxystomata, the 
Oxyrhyncha differ from them in their triangulate buccal cavity and position 
of afferent branchial channel; but Mesorhea approximates on the part of 
the Parthenopide to the Oxystomatous type. From the Cancroid Crabs 
(Cyclometopa) typical Maiid@ are distinguished by longitudinal antennules 
and position of basal antennule joint; the Parthenopide, however, occupying 
an intermediate place between the rest of the Oxyrhyncha and certain 
Cancroidea. The author summarized and reviewed the various classifications 
of Milne-Edwards (1834), De Haan (1839), Dana (1851-2), Alphonse Milne- 
Edwards (1860), Stimpson (1870), and Claus (1876), partly adopting the 
first and second primary groups of Dana, but with considerable modifications. 
His synoptical arrangement comprises (with short diagnostic characters) 
4 families, 12 subfamilies, 106 genera, and 14 subgenera, the characters of 
the families being thus defined :— 
Fam. I. Inacnipz. Hayes non-retractile or retractile against the sides 
of the carapace. No defined orbits exist, but there is often a well-developed 
preocular and postocular spine. Basal joint of antenne usually slender, 
sometimes moderately enlarged. 
Fam. II. Maups. Eyes retractile within the orbits, which are dis- 
tinctly defined, but often more or less incomplete below or marked with 
open fissures in their upper and lower margins. Basal antennal joint always 
more or less enlarged. 
Fam. III. Prricerips. Eyes retractile within the small circular and 
well-defined orbits, which are never incomplete as in the Maiide. Basal 
2B 
