THE LONG-TAILED MOLUCCA CRAB. 487 



with a lance was aimed at them. Tlie arm-like appendages of this creature are inserted into 

 the corner of the eye for nearly one-fourth of their length. This parasite attains to the 

 length of three inches. An allied species, called Lemceopoda galei, is found on one of the 

 common dog-fishes known by the name of tope, and described on page 199 of this volume. A 

 strange, elongated creature is the Penella filosa, so called from its extreme length. This 

 species is found to penetrate into the flesh of the sword-fish, the tunny, and the mole-iish, all 

 of which have been described in this volume. It is said to cause them considerable pain. 

 A parasite of even stranger form, but belonging to the same genus, is Penella sagittata. 

 One of these parasites, called the Sprat-sucker, is sometimes tolerably common, many 

 specimens being obtainable at a single fishmonger's shop, while for several years hardly one 

 will be seen. The color of this parasite is pale sea-green, with a slight bluish cast. The eggs 

 are very green. 



A strange and seemingly shapeless parasite, that is found to affix itself to the carp tribe, 

 is the Lernceocera cyprinacea,. The Lerncea, a creature of somewhat similar form, is notable 

 for being found upon the gills of the codfish. This creature belongs to the typical genus. 



PYCNOGONIDES. 



6 



It is hardly possible to imagine any forms that are so strange, any habits so astonishing 

 as those which are found in the crustaceans described in the following lines. Although they 

 have been known for some time, their proper place in the scale of creation has long been a 

 disputed point among systematic naturalists, some considering them to belong to the crusta- 

 ceans and others to the spiders. As, however, they undergo a true metamorphosis, which is 

 not the case with any spider, they are now admitted to be real, bat unique Crustacea. Even 

 such naturalists as Siebold and Milne-Edwards differed about them, the former placing them 

 among the spiders, and the latter ranking them with the Crustacea. 



Such strange creatures as these are not easily described, especially when the space that 

 can be granted to them is so limited, for their whole economy is so thoroughly unique that 

 they require a volume rather than a page. They are found upon the European coast, and 

 their history is briefly as follows. 



Two of these strange-looking creatures with wonderfully small bodies and enormous legs, 

 jointed and arranged in such a manner as almost to preclude the idea of their real character, 

 are called Pycnogonum littorale and PTioxichilidium coccinium. Indeed, it seems passing- 

 strange how the tiny abdomen can absorb sufficient nutriment for the supply of those marvel- 

 lous limbs. Their economy is as strange as their form. 



Some specimens of a well-known zoophyte (Coryne eximium) are often seen attached to 

 the rocks or sea-bed. The PTioxichilidium is frequently found as a nodule. In spite of the 

 long limbs, it appears packed away in a very complete manner, the limbs being rolled round 

 the body so as to form the creature into a kind of ball. During its growth the young Phoxi- 

 chilidium has to pass different stages. Sometimes it possesses the rudiments of limbs, with 

 long filamentous appendages ; sometimes it throws them off, and contents itself with a pair of 

 stout claws, and then again grows a fresh set of limbs and a pair of small and feeble claws. 



Strange as are these habits, there is still a kind of analogy with other modes of animal life. 

 On page 47-1 is mentioned the curious little crustacean which resides within the body of a beroe, 

 and in the present instance there is an evident analogy with the various galls and their inhab- 

 itants, the cells of the Phoxichilidium being in fact the galls of the coryne. 



SWORD- TAILED CRUSTACEA; XIPHOSURA. 



The Crustacea abound in strange forms. The Long-tailed Molucca Crab belongs to a 

 separate order, called by the name of Xiphosura, or Sword-tailed Crustacea, in allusion to the 

 long and sharp spine which projects from the shell. These creatures, of which several species 

 are known, can easily be recognized by their general shape. The body and limbs are covered 



