576 GEOLOGICAL SURVEY OF THE TERRITORIES. 



EXPLANATION OF PLATE XXXI. 



Fig. 1. Apas lucasanusFack. Seen from beneath. Enlarged 3|- times, wiii, mandibles. 



Fig. 2. Apus lucasanus Pack. First antennae. 



Fig. 2a. A2ms lucasanus Pack. End of the same magnified. The antennae of both 

 pairs drawn to the same scale. 



Fig. 3. Apus lucasanus Pack. Maxilla, showing the (a) anterior and (&) posterior di- 

 visions of the free edge ; max, the gill of the maxillipede. 



Fig. 3a. Ajms lucasanus Pack. Maxillipede, represented by the gill only. 



Fig. 4. Apus lucasanus Fack. First leg giving (with some changes) Lankester's nomen- 

 clature of the parts; ax^-ax*, the pseudojoints; en^-en^, the six enditeSj with 

 the gill and flabellum. 



Fig. 5. Apus iucasamis. The oostegite, or part of the 11th pair of legs of the female 

 containing the eggs; os, aperture of the sack; Jl, modified flabellum; x, the 

 greatlv enlarged subapical lobe' (compare Plate XVIII, figs. 2, 3, 4x, and 

 Plate XXXII, fig. 2x); br, the gill. 



Fig. 6. Limnetis brachyura (Europe). AnP, 1st antenute ; anP, 2d antennae ; lai, 

 labram ; sh. g, shell gland ; iiit, intestine ; ht, heart ; add. ms, adductor mus- 

 cle; oG, ocellus; ind, nsjandible; liv, liver. 



Fig. 7. Limnetis hracliyura. Section through the body and shell (s7t); ht, heart; int, 

 intestine; ov, ovary; 1-6, the six endites. 



Fig. 8. Limnetis hracliyura. Brain (6r) and nervous cord; ?i. ant^, origin of 1st anten- 

 nal nerve ; n. anP, 2d autennal nerve ; md. g, mandibular ganglion ; vix. g, 

 maxillary ganglion ; G^, G^, succeeding thoracic ganglia. Other letters as 

 in Fig. 7. 



Fig. 9. Distomum apodis Pack. Amer. Naturalist, vol. xvi, p. 142, Feb., 1882. Side 

 view, greatly enlarged. A parasite in oostegite of Apus lucasanus. 



Fig. 9 his. The same; ventral view. 



Fig. 1 drawn from nature by J. S. Kingsley ; Figs. 6-8 copied from Grnbe ; the others 



draA\ii with tbe camera by the author. 



