200 



HARDWICKE'S SC IE NC E- G O SS1P. 



LSe P t. 1, 1870. 



drawing, a portrait of one of our captives, drawn by 

 an expert ; and we shall be glad if any of them can 

 give us an authentic account of the habits and vital 

 economy of this curious family. 



A yellowish-brown object the size of a small pea 

 has been found clinging closely to the inside of the 

 bag ; it is an odd composite-looking creature 

 (fig. 186) ; it seems to be made up of parts of three 

 different and wholly incompatible animals. The 

 bulky central portion (the thorax or -n-tpaXov) is ar- 

 mour-plated, and of a pale chestnut colour ; while 

 the head and tail (ici(pa\ov and TrXiov) are opaque 

 white. The first might belong to some terrestrial 

 winged insect; while the last is the typically perfect 

 obpa of a marine crustacean. After much discussion, 

 an adept pronounces it to be a Praniza, or rather 

 the fully-developed larval form of a creature which, 

 after another moult, would be called Praniza by 

 those who follow Leach; but recent researches seem 

 to have proved that Praniza is not a distinct genus 

 or species, but is only the adult form of the female 

 of Anceus. The sexes are so wholly unlike each other 

 that for a long time they were described as distinct 

 species. "The Anceus of Risso, and the Praniza of 

 Leach, are respectively the adult male and the adult 

 female of one and the same species." 



Fig. 186. Praniza (fuliy-developed larva), x 10. 



Anceus is a genus of the Isopoda. The persever- 

 ance, conscientiousness, and determination with 

 which our leading naturalists follow up and unravel 

 the tangled mazes of the life history of the meanest 

 of living things, is well exemplified in the elaborate 

 chapter upon this genus in the work on the " Sessile- 

 eyed Crustacea," before referred to. In their early 

 stages both sexes are furnished with suctorial 

 mouths; "the females live parasitically upon fish, 

 burying their heads almost up to the eyes ; and we 

 repeat that we believe that up to the same period 



the male does also ; but with the adult moult the 

 female quits the parasitic life for a new kind of ex- 

 istence. With the adult moult the male gets rid 

 of the lanceolate oral appendages, and large pro- 

 jecting mandibles are developed. The oral appen- 

 dages of the female also undergo a great change : as 

 in the male, the lanceolate organs of the mouth are 

 lost ; but, unlike the male, they are replaced by no 

 other appendages." 



Fig-. 187- Head of adult male of Anceus maxillaris, x 20. 



Eig. 187 displays the head of the adult male, with 

 its formidable mandibles ; fig. 1S6, the fully- 

 developed larval form of the female, the creature 

 which we ourselves caught. The adult female is 

 very different in appearance. 



This cold, shapeless lump of dark quivering jelly, 

 not unlike a ripe grape saturated with water and 

 stripped of its skin, and not at all pleasant to touch, 

 undergoes a pleasing transformation when placed 

 in a bell-glass with some of its native element ; it 

 swells and expands, and stretches until it becomes 

 a gorgeous mollusc of emerald green, — aNudibranc/i, 

 of the family Doridcc, wearing his plumose lungs in 

 a coronal wreath on the hinder part of his broad, 

 fiat back ; his curiously-formed tentacles are far 

 back on his neck, with eye-specks at their roots ; 

 his skin is covered with vibratile cilia, and is full of 

 calcareous spicules ; he is all over little horns ; he 

 is the Polycera Lessonii of D'Orbigny. No doubt he 

 has just risen from his calm retreat amongst the 

 rocks under a tangled forest of Laminaria, after a 

 heavy supper of zoophytes and sponges, with per- 

 haps a bit of "dead man's thumb," Alcyonium digi- 

 tatum, by way of a finish, to take his evening stroll 

 at the top of the water, walking upon it, or rather, 

 just underneath it, with his back downwards, and 

 the expanded sole of his one flat foot turned up to 

 the veiled sky ; or he may have finished his after- 

 supper mile, and have been taking a comfortable 

 snooze, suspended from the surface by the tip end 

 of his tail (which he had previously buoyed by 

 throwing out a horizontal film of mucus), and 

 hanging head downwards, regardless of apoplexy. 

 Members of his family are often to be found under 

 shelves of rock at dead low water ; but they look 

 like anything but living things, and are generally 

 passed by with perhaps the remark, " Those must 

 be the eggs of something or another." They have 

 the power of producing a very curious sound, a kind 



