igii-] F. H. Stewart: Development and Anatomy of Cirripedes. 37 



V. — Post-larval development and anatomy of the male of Scalpellum gruvelii. 

 (i) The cyprid larva. 



(2) The pupa. 



(3) The adult. 

 VI. — Ibla cumingii. 



A. — Anatomy of the male. 



B. — Absence of rudimentary testes in the female. 

 VII. — Sensory hairs of Scalpellum squamuliferum, bengalense and gruvelii, and of 

 Ihla cumingii. 



XL— POST-LARVAL DEVELOPMENT OF SCALPELLUM 



SQUAMULIFERUM, WELT,, AND ANATOMY 



OF THE MALE. 



The expression post-larval development is intended to include the various stages 

 from the fixation of the cyprid larva to the attainment of adult form and complete 

 sexual maturity. 



A.— GENERAL OUTLINES OF THE DEVELOPMENT. 

 (i) The Hermaphrodite. 



(I) The Pupa. 



The general outlines of the development are so well known as to call for little 

 reference.^ Plate iv, fig. i, represents the cyprid during the course of the first 

 ecdysis. A younger cuticle bearing the hairs characteristic of the later stages has ac- 

 tually been formed under the bivalve shell of the cyprid, but is only visible in sections. 

 The two larval eyes {e.) are being cast off. The antennae are embedded in amass of 

 cement. The alimentary canal {ces. and st.) is already patent, the stomach filled 

 with a mass of excretory matter. The rudimentary testes can be distinguished in 

 sections as two minute cell-masses, one on either side of the stomach. The nervous 

 system consists of the cerebral ganglion {ce.g.) and the five ganglia of the ventral 

 chain {vn.c). The larval integuments are not furnished with sensory hairs. The out- 

 lines of the terga, scuta, carina and rostrum can already be distinguished, but are not 

 represented in the figure. 



The pupa measures i*i mm. in length. 



(2) The young Adui.t. 

 Figure i should be compared with pi. iv, fig. 2, taken from a young hermaphro- 

 dite measuring 2*5 mm. in length : ant. are again the embedded antennae. The 

 oesophagus now has a strong coat of circular muscles. The two caeca which arise 

 from the anterior end of the stomach were not visible in the preparation. All the 



Compare description of cypris of Lepas australis, Hoek (8, p. 6). 



