segment and a large spatulate, terminal seg- 

 ment ; even in those with a 1-segmented fifth 

 leg, such as the species of Pseudocucanthiis 

 Brian and Orbitacola.r Shen, the free segment is 

 still well developed and spatulate. The terminal, 

 spatulate segment of the bomolochids is usually 

 armed with one spine on the outer surface and 

 two spines and one seta at the distal end. 



GENUS TUCCA KR0YER, 1837 

 Diagnosis 



Type species is Tucca impressus Kr^yer, 

 1837. 



Female. — Body form and mouth parts as de- 

 fined for the family. Eggs multiserate ; egg 

 sacs cylindrical, longer than body. First an- 

 tenna 5- or indistinctly 6-segmented, basal 

 segment armed with a strong hook on ventral 

 surface. Second antenna 3-segmented, bearing 

 terminally five weak claws, three setae, and one 

 pectinate, lamelliform process; distal segment 

 covered with teeth posteriorly. Leg 1 biramous, 

 flattened, and 3-segmented, located on posterior 

 wall of ventral concavity in head. Leg 2 bira- 

 mous, 2-segmented. Leg 3 and leg 4 with 2- 

 segmented exopod and 1-segmented endopod ; 

 intercoxal plate missing. Leg 5 very small, a 

 single segment tipped with three setae. Leg 

 6 absent. 



Male. — Unknown. 



Remarks 



When Kroyer (1837) established this genus, 

 he gave almost no account of the appendages, 

 and neither did Nordmann (1864) in his de- 

 scription of West African specimens that he 

 called T. impressus. Consequently, lacking such 

 information, these authors were inconsistent in 

 the familial attribution of the genus Tucca. 

 Kr0yer placed it in the family Dichelestiidae 

 and Nordmann in the family Chondracanthi- 

 dae. Both Milne-Edwards (1840) and Bassett- 

 Smith (1899) followed Kr0yer's opinion. 



The nature of the mouth parts of Tucca was 

 not known until 1911, when Wilson studied the 

 specimens of Tucca in the collections of the 

 U.S. National Museum. According to his ob- 

 servations, he placed the genus in the subfamily 

 Bomolochinae of the family Ergasilidae, but 

 later, in 1932, he promoted the subfamily to the 

 familial level. 



Wilson's additional information on the mor- 

 phology of the .species of Tucca was, however, 

 correct only in the gross anatomy of the mouth 

 parts and not entirely right in the fine struc- 

 tures of the mouth parts and other appendages. 

 I discovered these eri'ors after restudying the 

 specimens of Tucca that had been studied by 

 Wilson in 1911 (the collections from Woods 

 Hole, Mass., and Beaufort, N.C.), in 1913 (the 

 collections from Montego Bay, Jamaica), and 

 in 1932 (the collections from Woods Hole, 

 Mass.). The new species, Tucca corpulentus, 

 described by him, is only a deformed specimen 

 of T. impressus; and some immature adult 

 females of T. impressus were mistaken by him 

 for adult males. As Vervoort (1962: 93-96) 

 and Yamaguti (1963: 43-44) were misled by 

 Wilson's inaccurate observations, their ac- 

 counts of the species of the genus Tucca should 

 be used with reservations. This problem is 

 discussed in more detail in a later section. 



The specimens described by Nordmann 

 (1864: 491-494, pi. VI, figs. 7-10) as T. im- 

 pressus were claimed by Wilson (1911: 359- 

 360) to be a new species, to which he gave the 

 name T. verrucosus. I refrain from making 

 any decision on the validity of T. verrucosus 

 without consulting either the original material 

 studied by Nordmann or other specimens col- 

 lected from the same locality (west coast of 

 Africa) and the .same host (Diodon sp.). If 

 Wilson's assumption is correct, then T. ver- 

 rucosus would naturally be the second species 

 of the genus ; however, I now prefer to treat the 

 genus as monotypic. 



A doubtful form, Tucca sp., was introduced 

 to the genus by Pearse (1952: 12, figs. 23-27). 

 This species, however, has been questioned by 

 Causey (1955: 11) as being probably a muti- 

 lated specimen of Blias prionoti Krttyer, 1864. 

 The mandible of Pearse's Tucca sp. is very 

 convincing evidence that it is not a tuccid. Its 

 foi'm of a "slightly curved hook" indicates a 

 chondracanthid type of mandible rather than a 

 tuccid type. 



TUCCA IMPRESSUS KROYER, 1837 



Tucca impressus Kr0yer, 1837, pp. 479-482, 

 pi. V, fig. 2(a-h). Milne-Edwards, 1840, p. 496. 

 Bassett-Smith, 1899, p, 469. Wilson, 1908, p. 



CYCLOPOID COPEPODS OF GENUS TUCCA 



287 



