88 AliTNUAL EEPOET. 



The Cyclopoidea are considered the highest group in the order, approaching 

 the Macroural Crustaceans. The body is not covered by a carapace, as in the 

 following tribes, and the abdomen is extended in the same line as the body, and 

 not incurved as in Daphnioidea, etc. The abdomen is terminated by two stylets 

 which bear several setse. If the Epizoa ai-e to be admitted into this tribe, certain 

 modifications would be necessary, which we need not discuss. 



The cephalothorax is composed of from four to seven segments. In those spe- 

 cies having four segments, the first bears the first and second antennse, mandi- 

 bles, maxillae, maxHlipods, first feet and one pair of natatorial feet, while the 

 following three carry the remaining pairs of natatores. 



Eyes of the three kinds : 1 . A pair of simple internal eyes with spherical lenses, 

 which are the ordinary kind. These are usually united near the front in a single 

 very small spot, though they are sometimes remote. 



2. A pair in an elevation on the under side of the head between the antennae. 

 The pigment is often like a piece of solid indigo. 



3. A pair of simple eyes consisting of an internal prolate lens situated at the 

 extremity of a vermiform ma?s of pigment and of a large oblate, lens-shaped 

 cornea. This kmd of eye is found in the Corycaeidse. 



Antennce. The antennae are of two pairs, of which the superior are organs of 

 locomotion, and usually are long and powerful. In the males of many species 

 one or both are modified to form a joint by which the female is held during 

 coition. These modifications are often of generic importance. 



The secondary antennae are subjected to greater changes and serve various 

 functions. Sometimes they are simple; in other species they have two rami. 

 They are often prehensile, and when simple the setae at the end are movable ao 

 that they assist the animal to creep on surfaces. 



The mouth is situated in the posterior aspect of a low prominence beneath the 

 head. 



The mandibles are variously modified. 



The maxillce are one to four jointed organs. 



The maxillipeds are always simple, or if dividea the branch is rudimentary. 



Anterior pair of legs (or second maxillipeds). These organs vary greatly in 

 form, and afford means of generic classification, and wiU be described under their 

 appropriate heads. 



Natatory feet. These are similar to those of other Entomostraca, bearing setae 

 for locomotion. There are four pairs, and sometimea a prehensile or abortive 

 pair following. 



The heart is situated in the posterior part of the thorax, and the circulation 

 may be watched as the blood globules circulate between the tissues ; particularly 

 in some transparent species of Calanidae these may be well traced in the thorax. 



Nervous system. A large ganglion exists over the mouth, and surrounds the 

 oesophagus. 



This tribe includes three families, as given by Dana, but the Epizoa must prob- 

 ably be included also. The family Corycceidm is oceanic, and no members have 

 been found in our locality. 



FAMILY I. Calanidae. 



Bibliography. — Dana, Wilkes' Explor. Ex,, p. 1039. 



Characters. — Eyes often of two kinds, the upper pair being simple and minute, 

 with their pigments either separate or collected into one. In 



