86 REPORT — 1869. 



somites of the pleon, and in the enormous development of two deciduous spines 

 on the base of second pair of antennce. 



Homarus marlnus. 



Common as the European Lobster is, it is very remarkable that a very young 

 si)eeimen has, as far as I know, never been met with. I have for several years 

 offered a reward for a very small specimen, but have never received one less 

 than 3 inches long from the rostrum to the telsou. Many years since Erdl, 

 in a memoir on the subject, described the young Homarus as being hatched 

 in the form of the adult animal. 



T have, during the last two summers that I have been engaged on this 

 Eeport, endeavoured to hatch and develope this among other forms. Having 

 specimens brought to me with ova, I have succeeded in hatching the same ; 

 but the mystery connected with the preservation of life, so as to enable us to 

 watch the development of the animal from one stage to the next, has yet to 

 be overcome. 



Thi'ough the kindness of Mr. Alford Lloyd, curator of the aquarium in the 

 Zoological Gardens at Hamburg, I have been enabled to obtain a specimen 

 hatched under his knowledge about eight days old. This enables me to 

 prove that not only is the young liatchcd in a form distinct from that of the 

 parent, but, while it has continued to increase in size, and therefore cast more 

 than a single moult, that it retains that form for some time after its birth. 

 The ovum is about one-tenth of an inch in diameter, and contains a vitellus of 

 a dark, almost black, green colour'. In the earlier stages of the develop- 

 ment of the embryo, the central or deciduous eye is distinctly seen, but 

 appears to be lost at the time of the escape of the larva from the egg-case ; 

 at this period the young animal has a short pointed rostrum, that at first is 

 bent back under the ventral surface of the ccphalon ; two large eyes, which 

 at first are bent under the lateral margin of the cephalou ; two pairs of short 

 antenna ; a non-appeudiculated mandible ; two pairs of maxillae, the third 

 pair or maxilliped being not yet developed ; seven pairs of pereiopoda, each of 

 which carries attached to the third joint a long secondary multiarticulated 

 ramus. The third pair is developed into a strong chelate organ, whilst the 

 fourth and fifth pairs have rudimentary processes attached to the distal 

 extremity of the fifth joint that demonstrates their chelate conditions at a 

 very early stage. The pleon consists of six somites only, neither of which is 

 furnished with a pair of appendages, or, as far as I could see, the rudiments 

 of them. The posterior somite or telson is dorsally and veutrally flattened, 

 evenly excavate at the posterior margin, which has the lateral extremities 

 produced to a shai'p point ; while a large strong spine projects posteriorly 

 from the centre, on each side of which, between it and the lateral point, are 

 about twelve short stout pointed hairs. 



Crangon vulgaris. 



The young of the common Shrimp, although I have read of its resemblance 

 to that of A. mysis, has not, I am convinced from that description, ever been 

 described from the form in which it appears at the period when it leaves the 

 egg- case. 



At this stage it has a long straight anteriorly projecting rostrum on the 

 carapace, a posteriorly projecting dorsal spine on the third somite of the 

 pleon, and a lateral one on the posterior margin on each side of the fifth 

 somite. The eyes are large, the antenna3 short ; the mandibles and two 

 pairs of maxillae, as well as the three anterior pairs of pereiopoda, are alone 

 developed, of which the three last are furnished with secondary appen- 



