NAT UR A. L HISTORY OF THE GENUS HERO. 
107 
Plate IV. 
Fig. 4. Dero Perrieri, as a transparent object, showing arrangement of blood- 
vessels &c. After Perrier. 
5. The same, in optical longitudinal section : a, integumental layer ; b, 
ciliated layer ; c, blood-vessels. From life. 
6. The same. Dorsal view of branchial area. From life. 
7. The same. Lateral view of branchial area. From life. X 30. 
8. Dero latissima. Dorsal aspect of branchial area. From life. X 80. 
9. Dero Mulleri. A similar view. From life, x 125. 
10. Setae of ditto: a, ventral seta of second to fifth segments ; b, hooted 
dorsal seta of the same segments. 
Plate V. 
Fig. 11. Dero limosa. Dorsal view of expanded area. From life. X 50. 
12. The same. Lateral view of expanded area. From life. X 50. 
13. The same. Dorsal view in outline. After Leidy. 
14. The same. Ventral view of contracted area. Photographed from life. 
15. The same. Ventro-lateral new. Photographed from life. 
16. Setse of D. limosa-. a, ventral seta of second to fifth segments; b, 
ventral seta of sixth and following segments ; c, hooked dorsal seta3. 
17. Dero fur cat a. Dorsal view of branchial area. From life. X 80. 
18. The same. Lateral view. From life. X 60. 
Notes on a. Collection of Crustacea from Singapore. 
By Alfred O. Walker, F.L.S. 
[Read 17th March, 1887.] 
(Plates VI.-IX.) 
Towards the end of the year 1S79 my friend Mr. F. Archer, of 
Liverpool, requested me to undertake the naming of a collection 
of Crustacea which his brother, Surgeon-Major Archer, was then 
sending over from Singapore. Pressure of other work and want 
of acquaintance witli exotic Crustacea, not to mention the fact 
of my residing at a distance from London (where alone the 
necessary works of reference can be procured), caused me to 
hesitate long before I undertook it ; and it was not until it became 
clear that nobody else in England would undertake the work 
(such is the scarcity of carcinologists) that I finally decided to 
do so. I may also add that had it not been for the kind assist- 
ance rendered by Mr. E. J. Miers, which gave me the start 
without which the task would have been almost impossible, I 
should have given it up at the outset. 
LINN. JOURX. — ZOOLOGY, YOL. XX. 
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