A STUDY IN MORPHOLOGY. 61 



Up to the present time our knowledge of the early stages of Lucifer has been 

 extremely meagre. 



In his report on the Crustacea of the United States Exploring Expedition, DANA 

 described (p. 634) an organism under the name of Erichthina demissa, and figured 

 it in plate 42, fig. 3. GLAUS ('Crustacean System,' p. 13) gives a figure of the same 

 organism at a latter stage of development, and calls attention to the numerous features 

 of resemblance to the Protozoea stage of development of Penceus. 



Only a few months before his death, the lamented WiLLEMoES-SuHM collected a 

 number of specimens of Erichthina in the South Pacific, and, associated with them, 

 a sufficient number of later stages to assure him that Erichthina is the larva of 

 Lucifer. His account (" Preliminary Ptemarks on the Development of some Pelagic 

 Decapods," by R. von WILLEMOES-SUHM, Ph.D., Proc. Eoyal Soc., Dec. 9, 1875, 

 p. 132-4) is very brief, and as it contains all that is known about the metamor- 

 phosis of this extremely interesting form, I quote it in full : 



" Very similar to that of Sergestes is the development of Leucifer. Here the earliest 

 Zoea of a species from the Western Pacific has got at first no eyes, then sessile ones 

 came out, and the animal then presents the form which DANA has called Erichthina 

 demissa, and which GLAUS suspected to be not a Stomatopod but a Schizopod larva. 

 After the second moulting this Erichthina gets stalked eyes, and very long setse 

 on all its appendages, becoming a rather long, very delicate Zoea. It now enters the 

 Amphion stage, but never gets more than four pairs of pereiopods, and loses another 

 pair of these when it moults for the youngest Leucifer stage, in which two pairs of 

 pei^eiopods are absent. 



" The next question after having found this out, was, of course, whether Amphion, 

 Sergestes, and Leucifer leave the egg as a Zoea, or whether there is a preceding Nauplius 

 stage. My own impression is that in the two first-named genera this is not the case, 

 as the youngest Zoeas which I ca,ught had all the same size, and as none of them was 

 without the large lateral stalked eyes. As for Leucifer, the question appears to me to 

 be doubtful ; for it is, from what I have seen, quite possible that my youngest Zoea, 

 which has only got a central eye, may be preceded by a Nauplius. Of course, the 

 simplest thing would be to get the eggs ; but there is the difficulty, for Amphion is 

 caught very rarely, and has never been obtained at any other time but between 

 8 and 12 P.M., when it is extremely difficult by lamplight to find out the youngest 

 stages. Senjcstes larvae are commoner, appearing also in the daytime, and Leucifer is 

 sometimes caught in abundance. I hope, therefore, that I shall succeed in completing my 

 researches about this question, especially as far as the two latter genera are concerned. 



" H.M.S. 'Challenger,' Honolulu, Sandwich Islands. 

 "July 30, 1875." 



As the sad death of this lamented naturalist, only a short time after, put an end to 

 tins as well as to his other researches in all departments of zoology, I take pleasure in 



