74 



Part III. — Twenty-third Annual Report 



In the sketch the exact number and arrangement of the hairs, &c, 

 has been attempted, except in the case of figs. 7 and 16, and the draw- 

 ings of the protopodite joints. The exact number of setae is not introduced 

 on the exopodites, pleopods, uropods, or, in certain cases, on the telson. 

 In the drawings of the complete larva the pereiopods are represented 

 semi-diagrammatically. 



The Appendages of the First Zoea. 



The appendages present in the first zoea stage are — (1) the Eyes; (2) 

 Antennules; (3) Antennae; (4) Mandibles; (5) First Maxillae; (6) Second 

 Maxillae; (7) First Maxillipedes ; (8) Second Maxillipedes ; (9) Third 

 Maxillipedes ; (10) First Pereiopods ; (11) Second Pereiopods ; (12) Third 

 Pereiopods ; (13) Fourth Pereiopods ; (14) Fifth Pereiopods. It possesses 

 all the cephalic and thoracic appendages which the adult has. The 

 telson is triangular. The pleopods and uropods are not yet developed. 



A detailed description is not necessary ; in addition to the drawing of 

 each appendage, short notes will be merely added here. 



Eye, o., fig. 4, pi. i. 



The eye is large, and has a very short stalk. 



Antennule, a., fig. 2, ib. 



The antennule is crowned with three aesthetascs, one of which is 

 specially large, and two hairs. A minute hair was found at the base of 

 the aesthetascs on the antennule of one side, but not on that of the other 

 side. A little short of the end of the antennule there is a little tubercle 

 surmounted by a short plumose hair. In Sars' drawing of the appendage 

 the plumose hair is shown larger than in the form here described. 

 Herrick's drawing of the antennule of the first stage of the American 

 lobster shows a more differentiated appendage. 



Antenna, A., figs. 1 and 24, ib. 



The endopodite or flagellum (fig. 24) is two-jointed. It bears on its 

 extremity four plumose setae. The antenna represented by Herrick has 

 a segmented or annulated endopodite. 



The scale of one side had 23 setae ; that of the other side had 25 



setae. 



Mandible, Mn., figs. 5, 6 and 18, ib. 



The apparent joint in the mandible (fig. 5) above the origin of the 

 palp seems to be simply the edge of its jointing with the cephalon. 



The two hairs on the palp (fig. 18) have their distal halves finely 



serrated. 



An enlarged drawing of the cutting edge of the mandible is shown in 

 %. 6. 



First Maxilla, lm., fig. 27, ib. 



On the lower lobe the group of four hairs which have been, for con- 

 venience, represented as pointed downwards, should be directed upwards. 



